Abstract
To analyze the change of functional movement of implants with the progression of periimplant tissue inflammation, we studied implant time-dependent displacement with vertical loading in healthy and experimental periimplant tissue inflammation.
Titanium screw implants were placed in 6 beagle dogs. Experimental periimplantitis was induced with nylon floss ligature around the implant neck. Implant displacement was measured at the baseline and each month for 6 months, after periimplantitis was induced using a laser displacement transducer under 10 g to 500 g of vertical loading. Periodontal parameters, such as probing pocket depth (PPD), probing attachment level (PAL), gingival crevicular fluid volume (Periotron ® value), tooth mobility (Periotest ® value), and X-ray assessment were measured in all subjects.
Results were as follows: 1) Vertical displacement of implants with healthy surrounding tissue was very small compared to healthy teeth. The time-dependent curve of movement of implants was completely different from that of natural teeth, indicating the presence of viscoelasticity, rather than an elastic response. 2) Severe bone resorption and soft tissue breakdown were observed after periimplantitis was induced, but the amount of implant displacement did not change significantly. 3) Once periimplantitis was induced, PPD, PAL, and Periotron increased, but the Periotest value was not statistically significant.
These results suggest that the movement of implants, which may affect function, did not change with the progression of periimplant tissue breakdown. When examining of implants, bone resorption and inflammatory response should be monitored in conjunction with mobility assessment. J Jpn Soc Periodontol, 44: 21-31, 2002.
